The present invention relates to a system for the information exchange through an optical medium.
Heretofore, the transmission of information has ordinarily been carried out by conducting electrical signals by way of wires, and a coaxial cable or the like has been employed for the transmission of information with a high bit rate. Recently, optical techniques have been introduced for the transmission of optical signals using optical fibers as high-speed and reliable transmission lines.
However, the exchanging of optical information still presents a problem in connection with the establishment of information networks. In most cases, use is now made of a system that converts the optical signals into electrical signals which are in turn exchanged or distributed. As a matter of course, such a system cannot benefit from the high-speed and wide band characteristics of optical transmission, and is not applicable to equipment requiring frequent exchange of information, as in the case of multiprocessor systems equipped with hundreds of processors.
Besides, a variety of proposals have been made concerning systems for exchange of information carried by light without transferring it into electrical signals. In one of these, optical signals are divided by half-mirrors and distributed. In another, optical signals are sequentially distributed over the course of time using a rotating mirror etc. to change the direction of transmission. In still another, each individual optical transceiver is coupled to associated transceivers through optical fibers. None of these is, however, able to provide satisfactory results.